Artificial turf comprising an agglomerate infill

ABSTRACT

An artificial turf surface includes an artificial turf carpet with a pile, wherein the artificial turf carpet includes a backing. The artificial turf carpet further includes artificial grass fibers. The artificial grass fibers are tufted into the backing. The artificial grass fibers form the pile. The artificial grass fibers are secured to the backing. The artificial turf surface further includes an artificial turf infill distributed within the pile, wherein the artificial turf infill includes irregularly shaped grains, wherein the grains include an agglomerate including at least one type of non-elastomeric thermoplastic. At least a portion of the grains have fibrous extensions.

FIELD OF THE INVENTION

The invention relates to artificial turf, in particular to artificialturfs with infill and also infill for artificial turf.

BACKGROUND AND RELATED ART

Artificial turfs are known as a carpet structure resembling naturalgrass. The structure consists of a fabric to which fibers are tufted andfixed at the bottom side of the fabric. The fibers are monofilamented ortwisted yarns of polyethylene or other thermoplastic materials. Thefabrics are woven goods made of polypropylene and the fixing materialwhich glues the fibers to the fabric are mixtures of SBR latices andfillers such as calcium carbonate or polyurethane-based adhesives.

Artificial turfs are used as sports fields whereas the carpets are laidonto a substructure of rubber granules acting as a shock damping layeror onto a substructure that comprises an elastic layer (e-layer). Thecarpet structure is filled with sand and rubber granules in order tokeep the structure in place so that the carpet does not slip and thefibers stay in an upright position. The filling material is alsoreferred to as infill or infill material. Typically in use is SBR-rubberor EPDM-rubber, both elastomeric materials in irregularly granulatedform. The SBR-rubber is commonly sourced from used tires.

An advantage of using artificial turf is that it eliminates the need tocare for a grass playing or landscaping surface, like regular mowing,scarifying, fertilizing and watering. Watering can be e.g. difficult dueto regional restrictions for water usage. In other climatic zones there-growing of grass and re-formation of a closed grass cover is slowcompared to the damaging of the natural grass surface by playing and/orexercising on the field. Artificial turf fields though they do notrequire a similar attention and effort to be maintained, may requiresome maintenance such as having to be cleaned from dirt and debris andhaving to be brushed regularly. This may be done to help fibers stand-upafter being stepped down during the play or exercise. Throughout thetypical usage time of 5-15 years it may be beneficial if an artificialturf sports field can withstand high mechanical wear, can resist UV, canwithstand thermal cycling or thermal ageing, can resist inter-actionswith chemicals and various environmental conditions. It is thereforebeneficial if the artificial turf has a long usable life, is durable,and keeps its playing and surface characteristics as well as appearancethroughout its usage time.

The infill of synthetic turfs plays a predominant role concerning themechanical properties of the complete turf structure. These propertiesdetermine the damping of a bouncing ball and running or jumpingathletes. It is also desirable that the uppermost structure of a turfwould not cause injuries of the athletes, such as burns, scratches, skinabrasions, etc. Filling a synthetic turf only with sand would have anunpleasant effect of energy-sapping, comparable to running on dry sandon a beach. To avoid such uncomfortable attitudes infill systems arecommonly in use. At least two layers built up such infill systems,whereas the sand layer is laid first on top of the carpet topping (theopposite side of the backing) and a second layer or elastomeric materiallaid onto the sand. The elastomeric material normally consists of groundrubber, whereas the particles are coarser than the sand grains. Thethickness of an infill system is such that only a small proportion ofthe grass fibers exceed the infill layer in height. The completestructure then resembles freshly mowed natural grass.

The FIFA (Federation Internationale de Football Associaton) has set upquality standards in their ‘Quality Concept for Football Turf, Handbookof Requirements, January 2012 Edition.’ In this handbook, the standardsare described as well as the test methods. For synthetic turf infillsystems, the following holds:

-   force reduction: 60%-70%-   vertical deformation: 4 mm-10 mm-   rotational resistance: 30 Nm-45 Nm    all of which in dry and wet condition and after simulated wear.

According to the FIFA standards the tests are carried out with aso-called advanced artificial athlete—Triple A, a Lisport wear testerand a rotational resistance tester. Artificial turf or artificial grassis surface that is made up of fibers which is used to replace grass. Thestructure of the artificial turf is designed such that the artificialturf has an appearance which resembles grass. Typically, artificial turfis used as a surface for sports such as soccer, American football,rugby, tennis, golf, for playing fields, or exercise fields.Furthermore, artificial turf is frequently used for landscapingapplications.

Artificial turf may be manufactured using techniques for manufacturingcarpets. For example, artificial turf fibers which have the appearanceof grass blades may be tufted or attached to a backing. Often timesartificial turf infill is placed between the artificial turf fibers.Artificial turf infill is a granular material that covers the bottomportion of the artificial turf fibers. The use of artificial turf infillmay have a number of advantages. For example, artificial turf infill mayhelp the artificial turf fibers stand up straight. Artificial turfinfill may also absorb impact from walking or running and provide anexperience similar to being on real turf. The artificial turf infill mayalso help to keep the artificial turf carpet flat and in place byweighting it down.

United States patent application US 2010/0151158 discloses a method forrecycling synthetic turf that includes agglomerating a plurality ofsynthetic turf fragments and extruding the agglomerated material. Themethod produces a recycled material for use as infill in a syntheticturf. The agglomerate is extruded and may be in a spherical,cylindrical, oval, or football shaped. The pellets may also be of anirregular shape. The irregular shape may be used to aid tight packing ofthe granules.

SUMMARY

The invention provides for an artificial turf surface, a method, and theuse of an agglomerate as infill for artificial turf. Embodiments aregiven in the dependent claims.

Examples may provide for an artificial turf infill that is at leastpartially made from an agglomerate comprising one or morenon-elastomeric thermoplastics. The agglomerate is formed intoirregularly shaped grains. A “grain” as used herein encompasses a smallpart or portion of a material that is hard.

Normally, non-elastomeric thermoplastics would be too hard and rigid touse as an artificial turf infill. However, forming them into grains thathave fibrous extensions makes them flexible. When the grains aredistributed in the pile of the artificial turf, the grains have atendency to pack loosely because of the fibrous extensions. Thisproduces voids or free space between the grains which makes theresultant infill more elastic although it has been manufactured fromnon-elastomeric thermoplastics.

In various examples, the agglomerate may be formed my one or morenon-elastomeric thermoplastics and an additional additives such as apigment powder.

In some examples, the artificial turf infill that is at least partiallymade from an agglomerate of at least two non-elastomeric thermoplastics.

In other examples, material used to form the artificial turf infill isprovided as an agglomerate. An extrusion process or an agglomerationprocess is then used to form the material into the grains with fibrousextensions.

In one aspect, the invention provides for an artificial turf surfacecomprising an artificial turf carpet with a pile. The artificial turfcarpet comprises a backing. The artificial turf carpet further comprisesartificial grass fibers. The artificial grass fibers are tufted into thebacking. The artificial turf grass fibers form the pile. The artificialgrass fibers are secured to the backing.

The artificial turf surface further comprises an artificial turf infillwhich is distributed within the pile. The artificial turf infill mayalso be described as being distributed between the artificial grassfibers. The artificial turf infill comprises irregularly shaped grains.The grains comprise an agglomerate comprising at least one type ofnon-elastomeric thermoplastic. Alternatively the grains can be describedas comprising an agglomerate comprising at least one type ofnon-elastomeric thermoplastic. At least a portion of the grains havefibrous extensions.

In some examples all or a majority of the grains have the fibrousextensions. In other examples at least 40% 50%, 60%, 70%, 80%, or 90% ofthe grains have the fibrous extensions. A fibrous extension as usedherein encompasses a region of the grain that is substantially narrowerthan another portion of the grain. The material of the grain may berigid, but the fibrous extension is narrow enough that the fibrousextension is able to flex or bend.

The use of the irregularly shaped grains as the artificial turf infillmay have several benefits. One potential benefit is that thenon-elastomeric thermoplastics can be used. Normally the artificial turfinfill is made up of an elastomeric material or material which is easilypushed aside so that the artificial turf surface has lifelike propertiessuch as mimicking the give of a real turf surface which has dirt or sandwithin it. The irregularly shaped grains have the benefit that there maybe air pockets and the packing ratio of the artificial turf infill isreduced. This allows the hard non-elastomeric thermoplastics to be usedand still have the properties which realistically mimic a real turfsurface.

In another embodiment, at least 50%, at least 60%, at least 70%, atleast 80%, at least 90%, or at least 95% of the irregularly shapedgrains have a curved profile. Increasing the proportion of irregularlyshaped grains with a curved profile may have the effect of increasingthe amount of cavities or voids formed within the artificial turfinfill. This may in turn provide for better shock absorption by theartificial turf infill.

In another embodiment, at least 40%, 50%, 60%, 70%, 80%, or 90% of thegrains have the fibrous extensions. This embodiment may be beneficialbecause increasing the number or amount of fibrous extensions mayprovide for better shock absorption by the grains.

In another embodiment, in at least 50%, 70%, or 90% of the portion ofthe grains the fibrous extensions comprise at least 30% of the weight ofthe grains. This embodiment may be beneficial because increasing thenumber or amount of fibrous extensions may provide for better shockabsorption by the grains.

In another embodiment, the at least one type of non-elastomericthermoplastic is viscoelastic at temperatures below 100° C.

In another embodiment, the at least one type of non-elastomericthermoplastic comprise recycled artificial turf fibers. Recycledartificial turf fibers are equivalent to artificial grass fibers. Therecycled artificial turf fibers are artificial turf fibers which havebeen removed from a previously installed artificial turf surface. Theuse of the non-elastomeric thermoplastics from recycled artificial turffibers may have the benefit that the reuse of the thermoplastic reducesthe amount of waste which is deposited in landfills. It may also havethe benefit that the recycled artificial turf fibers may have additiveswhich would be useful for the artificial turf infill. For instance, therecycled artificial turf fibers may be colored green. Having theartificial turf infill a green color may be beneficial in making theartificial turf surface more lifelike looking. It may also have thebenefit that the recycled artificial turf fibers have other additivessuch as UV protection which will increase the longevity of theartificial turf infill.

In another embodiment, the irregularly shaped grains have alongitudinally stretched out and curved volume expansion with ratios oflength to diameter/cross sectioned within 1:2 to 1:50.

In another embodiment, the irregularly shaped grains have alongitudinally stretched out and curved volume expansion with ratios oflength to diameter/cross-section within any one of the following: 1:4 to1:50, 1:8 to 1:50, 1:16 to 1:50, and 1:32 to 1:50. This embodiment maybe beneficial because as the irregualry shaped grains become narrowerwith respect to their length the irregularly shaped grains may becomemore flexible.

In another embodiment, the irregularly shaped grains have a sieve sizebetween 0.2 mm and 12 mm. In this embodiment the irregularly shapedgrains have been selected such that they pass through a first sieve withan opening of 12 mm or less. The irregularly shaped grains are furtherselected such that they are captured by a sieve with openings of 0.2 mmor greater. The opening of the first sieve remains greater than theopening of the second sieve.

In another embodiment the irregularly shaped grains have a sieve sizebelow 12 mm. In this embodiment the irregularly shaped grains have beenselected such that they pass through a sieve with an opening of 12 mm orless.

In another embodiment, the irregularly shaped grains have a thicknessbetween 0.5 mm and 2 mm.

In another embodiment, the at least one type of non-elastomericthermoplastic comprise any one of the following: at least onethermoplastic polymer, a polyolefin, waste plastic, fibrous wasteplastic, pre-consumer yarn, post-consumer yarn recovered from syntheticsports fields, artificial turf fiber, recovered waste plastic, recycledpackaging material, poly ethylene food packaging, poly ethylene,polypropylene, a poly ethylene and poly propylene mixture, LLDPE, HDPE,LDPE, MDPE, PP, PE, a polyolefin, and combinations thereof. Thisembodiment may be beneficial because thermoplastic which would normallybe disposed of may be used for manufacturing a high quality artificialturf surface.

In another embodiment, the artificial turf surface further comprises asand layer between the backing and the artificial turf infill. The useof the sand layer between the backing and the artificial turf infill mayfurther serve to improve the replication of natural turf surfaceproperties by the artificial turf surface. The use of the sand layer mayalso reduce the amount of artificial turf infill which is required to beused.

In another embodiment, the majority of the irregularly shaped grainshave a curved profile. The curved profile may be in a cross-sectionalview of the irregularly shaped grain. Having a curved profile may bebeneficial because it may reduce how closely the irregularly shapedgrains can be packed next to each other. Having them less dense may bebeneficial because the artificial turf infill will have a more springyor elastic profile although the agglomerate is made of a non-elastomericthermoplastic.

In another embodiment, the fibrous extensions of the irregularly shapedgrains interlock with any one of the following: the artificial grassfibers, the fibrous extensions of other irregularly shaped grains, andcombinations thereof. This embodiment may be beneficial because theinterlocking of the fibrous extensions may serve to hold the irregularlyshaped grains in the same position with respect to each other, and alsopossibly to help hold their position relative to the artificial grassfibers. This may for example have the benefit of reducing the splasheffect when a ball hits an artificial turf surface. Splash is when theimpact of a ball or other object causes artificial turf infill to fly upabove the surface of the artificial turf surface. It resembles thesplash of an object hitting a puddle of water.

In another embodiment, at least a portion of the fibrous extensions arebranched. The branching of the fibrous extensions may be beneficialbecause it may make the fibrous extensions more flexible. The branchingmay also produce hook like structures that enable the irregularly shapedgrains to better interlock either with themselves or artificial grassfibers.

In another embodiment, the artificial turf surface further comprises atop infill layer. The irregularly shaped grains are between the backingand the top infill layer.

In another embodiment, the top infill layer comprises regularly shapedgranules. The regularly shaped granules may for example have round,oval, a rounded, or bead shaped appearance. The use of the regularlyshaped granules may be beneficial because it may have the effect ofreducing the friction between an object sliding on the artificial turfsurface and the irregularly shaped grains.

In another embodiment, the regularly shaped granules comprises at least50%, 70%, 90%, or 95% of the top infill layer by weight. This embodimentmay be beneficial because as the amount of the regularly shaped granulesincreases in the top infill layer the friction between an object slidingon the artificial turf surface is further reduced.

In another embodiment, the top infill layer consists of the regularlyshaped granules.

For example, the regularly shaped grains could be made from anagglomerate that is similar or has an equivalent composition to theirregularly shaped grains. In other examples the regularly shapedgranules could be made from a elastomeric compound such as crumb rubberor other materials conventionally used as artificial turf infill. Forexample, the elastomeric granulates used for artificial turf infillcould be placed on the surface artificial turf infill formed by theirregularly shaped grains. This may reduce the amount of elastomericgranulates that are used. As a smaller amount of the elastomericgranulate is used, it may reduce the splash effect when a ball or otherobject impacts the artificial turf surface.

In another embodiment, the regularly shaped granules comprise any one ofthe following: a least one thermoplastic polymer, a polyolefin, wasteplastic, fibrous waste plastic, pre-consumer yarn, post-consumer yarnrecovered synthetic sports fields, artificial turf fiber, recoveredwaste plastic, recycled packaging material, poly ethylene foodpackaging, EPDM, LLDPE, HDPE, LDPE, MDPE, PP, PE, a polyolefin, anelastomeric compound, rubber, crumb rubber, and combinations thereof.

In another embodiment, the top infill comprises elongated granules. Insome examples, the elongated granules may comprise an elastic orflexible material. The use of the elongated granulates in the top infillmay have several advantages. First, the elongated shape may help the topinfill to remain above or covering the infill made from the irregularlyshaped grains. The elongated shape may, in some examples, result in lessfriction between a person or object sliding on the artificial turf. Theuse of the elongated granules may also reduce the splash effect when aball or other object impacts the artificial turf surface.

In another embodiment, the elongated granulate are formed from any oneof the following: an elastomeric compound, shavings from a block of anelastomeric compound, rubber, crumb rubber, EPDM, and combinationsthereof.

In another embodiment the elongated granulate are shavings formed from ablock of an elastomeric compound. The use of the shavings from anelastomeric compound may make the artificial turf surface appear morerealistic. The use of shavings from an elastomeric compound may alsomake the shaving have a fiber like structure that helps to keep them inplace and reduce the splash effect.

In another embodiment, the top infill comprises at least 40%, 50%, 60%,70%, 80%, 90%, or 95% of the elongated granules by weight. Thisembodiment may be beneficial because it may provide for an artificialturf surface that is less likely to damage or irritate the skin of aplayer when sliding on the playing surface. The reduction of the splasheffect may also increase with a larger proportion of the elongatedgranules in the top infill.

In another embodiment, the top infill consists of the elongatedgranules. This embodiment may have the benefit of further reducing thesplash effect.

In another embodiment, the artificial turf surface further comprises asand layer between the backing and the artificial turf infill. Theartificial turf surface further comprises a top infill layer, whereinthe irregularly shaped grains are between the backing and the top infilllayer. The top infill comprises irregularly shaped granulate. Theirregularly shaped granulate comprises shavings from a block of anelastomeric compound. This embodiment may be beneficial because theirregularly shaped granulate may provide shock absorbency and also mayreduce the friction between an object sliding on the artificial turfsurface and the irregularly shaped grains.

In another aspect, the invention provides for a method of manufacturingan artificial turf system. An artificial turf system as used hereinencompasses the components which are supplied to manufacture anartificial turf surface.

The method comprises providing an artificial turf carpet with a pile.The artificial turf carpet comprises a backing. The artificial turfcarpet further comprises artificial grass fibers. The artificial grassfibers are tufted into the backing. The artificial grass fibers form thepile surface. The artificial grass fibers are secured to the backing.

The method further comprises agglomerating the at least one type ofnon-elastomeric plastic into an agglomerate for forming irregularlyshaped grains to provide an infill for the artificial turf carpet.

In another embodiment, the agglomeration of the at least one type ofnon-elastomeric thermoplastic into the agglomerate and the forming ofthe irregularly shaped grains form the agglomerate is performed using anagglomerator. An agglomerator as used herein is a device which appliesheat and pressure to agglomerate multiple thermoplastics into a singlestructure. The agglomerator may also cut or break the agglomeration intothe irregularly shaped grains.

The use of an agglomerator may be beneficial because it may provide foran inexpensive means of manufacturing irregularly shaped grains.

In another embodiment, the agglomerator is a friction agglomerator. Thefriction agglomerator may have one or more moving portions which usefriction to generate the heat necessary to form the agglomerate.

In another embodiment, the agglomerator is a disc agglomerator. The discagglomerator may have one or more rotating discs which receive theheated non-elastomeric thermoplastic and agglomerate them into theagglomerate and form the irregularly shaped grains at the same time.

In another embodiment, the forming of the irregularly shaped grains fromthe agglomerate is performed using an extruder. The use of an extrudermay be beneficial because the properties of the irregularly shapedgrains may be precisely controlled. An extruder as used hereinencompasses a device which heats the at least one type ofnon-elastomeric thermoplastic and then forces them through an orifice toextrude them. There may also be a device which cuts the extrudedagglomerate into the irregularly shaped grains. The material extrudedfrom the extruder may be referred to as an extrudate. However, theextrudate is the agglomerate.

In another embodiment, the extruder comprises any one of the following:an underwater pelletizing system, a water ring pelletizing system, astrand pelletizing system, and a hot-cut pelletizing system.

In another embodiment, the extruder optionally comprises a pelletizer orgranulation system to additionally form the shape of the irregularlyshaped trains.

In another embodiment, the forming of the irregularly shaped grains isperformed using an extruder. The use of an extruder may be beneficialbecause it may allow for precise control of the properties of theirregularly shaped grains such as the length, the amount of curvature ofthe grain, and the relative size distribution.

In another embodiment, the extruder comprises an extrusion die plate.The extrusion die plate has at least one orifice for extruding theagglomerate. The at least one orifice has a first portion and anopposing portion. The first portion is rough. The opposing portion issmooth to form irregularly shaped grains that have a curved profile. Thefirst portion, which is rough, causes a breaking or slowing effect asthe agglomerate is extruded. This causes the resulting irregularlyshaped grain to have a curved profile. This may be beneficial in that itmay cause the irregularly shaped grains to pack less densely. This maycause them to have a more elastic behavior although they are made from anon-elastomeric thermoplastic.

In another embodiment, the extruder comprises multiple orifices. Themultiple orifices have at least two distinct sizes. This embodiment maybe beneficial because the size distribution of the irregularly shapedgrains and their relative frequency can be precisely controlled.

In another embodiment, the multiple orifices may have an irregular shapeor profile. The use of the irregular shape or profile may have thebenefit of producing grains of agglomerate that are irregularly shaped.

In another embodiment, the extruder comprises a cutting system forcutting irregularly shaped grains.

In another embodiment, the cutting system of the extruder is configuredfor producing irregularly shaped grains with varying lengths. This mayfor instance be achieved by controlling how often the cutting systemcuts off extrudate (the agglomerate) that is being extruded. By varyingthe times between when the agglomerate is cut or choosing a distributionof times the relative size distribution of the irregularly shaped grainscan be controlled.

In another embodiment, the method further comprises mixing at least oneadditive into the agglomerate before forming the irregularly shapedgrains. This may be beneficial in adding various properties to theirregularly shaped grains such as flame retardants, UV protection, ordyes to color to change the appearance of the artificial turf infill.

In another embodiment, the at least one additive comprises any one ofthe following: a colorant or dye, a UV stabilizer, a flame retardant, afiller, a blowing agent, an anti-seize agents, a lubricant,compatibilizer, a binding agent, and combinations thereof.

In another embodiment, the method further comprises recycling usedartificial turf to provide the at least one of the at least one type ofnon-elastomeric thermoplastic. This may be beneficial in that it mayreduce the environmental impact of installing a new artificial turfsurface. It may also have the benefit that the thermoplastic recoveredfrom the used artificial turf may have additives such as colorants or UVstabilizers or flame retardants that are already present. This mayreduce the cost of manufacturing a new artificial turf surface.

In another embodiment the agglomerate at least comprises 80%, 90%, 95%,or 99% by weight the at least one type of non-elastomeric thermoplastic.In other words the agglomerate is at least 80%, 90%, 95%, or 99% (byweight) made from the at least one non-elastomeric thermoplastic.Increasing the amount of the non-elastomeric thermoplastic may have thebenefit of increasing the mechanical stability of the fibrousextensions. If other materials such as sand or elastomeric materials aremixed into the agglomerate the irregularly shaped grains may bestructurally compromised.

In another embodiment the agglomerate consists of the at least one typeof non-elastomeric thermoplastic. This embodiment may be beneficialbecause the agglomerate is completely made from the at least one type ofnon-elastomeric thermoplastic. Although the agglomerate is made from thenon-elastomeric thermoplastic it is flexible due to the fibrousextensions. The fibrous extensions are less likely to break apart whenformed entirely from the at least one type of non-elastomericthermoplastic.

In another embodiment the irregularly shaped grains consist of theagglomerate. This may provide for better structural integrity of theirregularly shaped grains.

In another aspect, the invention provides for a method of manufacturingan artificial turf surface. The method comprises a method ofmanufacturing an artificial turf system according to an embodiment. Themethod further comprises installing the artificial turf carpet. Themethod further comprises distributing the irregularly shaped grainswithin the pile and between the artificial grass fibers to form theartificial turf.

In another embodiment, the method of manufacturing the artificial turfsurface comprises distributing a sand layer within the pile beforedistributing the irregularly shaped grains.

In another aspect, the invention provides for use of an agglomerate asinfill for artificial turf. The agglomerate comprises irregularly shapedgrains formed for at least one type of non-elastomeric thermoplastic. Atleast a portion of the grains may have fibrous extensions.

It is understood that one or more of the aforementioned embodiments ofthe invention may be combined as long as the combined embodiments arenot mutually exclusive.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following embodiments of the invention are explained in greaterdetail, by way of example only, making reference to the drawings inwhich:

FIG. 1 illustrates an example of an artificial turf surface;

FIG. 2 illustrates a further example of an artificial turf surface;

FIG. 3 illustrates an examples of an irregularly shaped grains;

FIG. 4 illustrates an example of an agglomerator;

FIG. 5 illustrates an example of an extruder;

FIG. 6 illustrates an example of an extrusion die plate;

FIG. 7 illustrates an example of an artificial turf system;

FIG. 8 illustrates a further example of an artificial turf surface;

FIG. 9 illustrates a further example of an extrusion die plate; and

FIG. 10 illustrates a further example of an artificial turf surface.

DETAILED DESCRIPTION

Like numbered elements in these figures are either equivalent elementsor perform the same function. Elements which have been discussedpreviously will not necessarily be discussed in later figures if thefunction is equivalent.

FIG. 1 shows an example of an artificial turf surface 100. Theartificial turf surface 100 is formed by an artificial turf carpet 102that has a pile 104. The artificial turf carpet 102 comprises a backing106. Into the backing there are artificial grass fibers 108 that aretufted 110 into the backing 106. The pile 104 is formed from theartificial grass fibers 108. The artificial grass fibers 108 may forinstance be formed from a thermoplastic yarn or artificial grass. Thebacking 106 may be placed onto a base layer 112. The base layer may takedifferent forms in different examples. In one example the base layer issimply the ground. The artificial turf carpet 102 may simply be placedon the ground. In other examples the base layer 112 may have differentcomponents for providing drainage, and absorption of shock from athletesor other users of the artificial turf surface 100.

Within the pile 104 and between the artificial grass fibers 108 isspread an artificial turf infill 114. In this case the infill 114comprises irregularly shaped grains 116. The irregularly shaped grainsare formed from an agglomerate comprising at least one type ofnon-elastomeric thermoplastic. The non-elastomeric thermoplastics mayalso be thermoplastic polymers. The use of the irregularly shaped grainscauses voids 118 between a number of the irregularly shaped grains 116.These voids provide give and elasticity to the irregularly shaped grains116 that are made of what is considered normally a rigid thermoplastic.This enables a material which would normally be unsuitable for makingartificial turf infill function well. The artificial turf infill 114 mayprovide for helping the artificial grass fibers 108 to stay rigid and inthe correct position. They may also provide for shock absorption orother physical properties which help the artificial turf surface 100more approximate the properties of a real turf surface.

FIG. 2 shows a further example of an artificial turf surface 200. Theartificial turf surface 200 is similar to the artificial turf surface100 shown in FIG. 1. However, in this example there is additionally alayer of sand between the backing and the infill 114. The example shownin FIG. 2 may further approximate the properties of real turf moreaccurately. The use of the infill 114 with the irregularly shaped grains116 may provide a more lifelike and elastic surface than when sand 202is used alone.

FIG. 3 shows a photograph of a number of irregularly shaped grains 116.The irregularly shaped grains comprise at least one non-elastomericpolymer. The photograph shows that at least some of the irregularlyshaped grains comprise fibrous extensions 302. Not all of the fibrousstructure of the extensions is visible in the photograph. Some of thegrains also show fibrous extensions 302 with a branched structure 304.Some of the fibrous extensions 302 also have a hook like structure 306.The branched structure 304 or hook like structure 306 may help theirregularly shaped grains interlock with themselves and/or artificialgrass fibers. thermoplastics.

The irregularly shaped grains in FIG. 3 were tested as artificial turfinfill. Although made from rigid thermoplastics they exhibited shockabsorbency. Recycled SBR rubber infill was compared to irregularlyshaped grain infill of two different sizes. The first size ofirregularly shaped grain infill had a characteristic dimension of lessthan 2.5 mm. The second size had a characteristic dimension greater than2.5 mm. A sieve with a 2.5 mm screen was used to separate the two. Inthe experiment the force reduction of a soccer ball hitting the surfacewas measured for three consecutive hits at the same location for eachhit. The results are summarized in the table below

SBR infill agglomerate agglomerate As benchmark <2.5 mm >2.5 mm Forcereduction 1st hit 32.8% 40.3% 36.6% Force reduction 2^(nd) hit 19.3% 9.8% 25.7% Force reduction 3^(rd) hit 15.8%  6.1% 19.8%

In the above table it can be see that the agglomerate infill made fromthe irregularly shaped grains has a shock absorbency that is comparableto the SBR infill made from recycled black crumb rubber. In fact, thelarger grains (greater than 2.5 mm) surprisingly showed shock absorbencythat was greater than the SBR infill material for all three impacts.

FIG. 4 shows an example of an agglomerator 400. The agglomerator has ahopper 402 for receiving waste thermoplastic 404. A feeder 406 thenfeeds the waste thermoplastic 404 into a an agglomerator 408 whichcomprises a rotating disc and a stationary portion The agglomerator 408may heat and compress the waste thermoplastic 404. The rotating disc 408may have veins or gear-like surfaces which compress and cut the wastethermoplastic 404 into the irregularly shaped grains 116.

FIG. 5 shows an example of an extruder 500. The extruder again has ahopper for receiving waste thermoplastic 404. The waste thermoplastic isthen fed by a feeder 406 which heats and forces the waste thermoplasticthrough an orifice through an extrusion die plate 504. A cutting system506 then cuts agglomerate that is extruded from the orifice 502 into theirregularly shaped grains 116. The rate at which the cutting system 508cuts the agglomerate will control the length of the irregularly shapedgrains 116. The rate of the cutting system 506 can be varied to producea distribution of lengths of irregularly shaped grains 116.

FIG. 6 shows an example of an extrusion die plate 504 with an orifice502. The orifice 502 has a first portion 600 and an opposing portion602. The first portion 600 is rough and the opposing portion 602 issmooth. This modification will cause material extruded from the orifice502 to have a curvature to it.

FIG. 7 shows a flowchart which illustrates a method of manufacturing anartificial turf system. First in step 700 an artificial turf carpet 102such as shown in FIG. 1 or 2 is provided. Next in step 702 irregularlyshaped grains 116 are manufactured using the machine such as isillustrated in FIG. 4 or 5. At least one type of non-elastomericthermoplastic is either provided as an agglomerate or formed withanother material such as a second elastomeric thermoplastic or a dye inpower form. The agglomerate is then forced into the irregularly shapedgrains 116. In some examples, the agglomeration process is used to formthe irregularly shaped grains. In other examples, an extruder oragglomerator is used to form the agglomerate into the irregularly shapedgrains.

FIG. 8 shows a further example of an artificial turf surface 800. Theartificial turf surface 800 is similar to the artificial turf surface200 shown in FIG. 2. However, in this example there is additionally atop infill layer (801) that comprises regularly shaped granules 802. Thetop infill layer (801) is on top of the irregularly shaped grains 114.The use of the regularly shaped granules 802 have the advantage ofreducing the friction when something slides on the surface of theartificial turf surface 800. The regularly shaped granules 802 may bemade of several different materials. In one example the regularly shapedgranules are made from a agglomerate comprising at least one type ofnon-elastomeric thermoplastic. In another example the regularly shapedgranules are made from an elastomer.

FIG. 9 illustrates another example of an extrusion die plate (504)similar to that shown in FIG. 6. The extrusion die plate has a number oforifices 502′ for extruding the irregularly shaped granules. Theorifices have a variety of different sizes. The relative sizes of theorifices can be used to generate a distribution of grains with differentsizes. The shape or profile of the orifices can also be modified to aidin providing the grains with an irregular shape.

FIG. 10 shows a further example of an artificial turf surface 1000. Theartificial turf surface 1000 is similar to the artificial turf surface800 shown in FIG. 8. However, in this example the top infill layercomprises either elongated granules 1002 and/or irregularly shapedgranulate 1002 on top of the irregularly shaped grains 114. The use ofthe elongated granules 1002 and/or irregularly shaped granulate 1002 mayhave the advantage of reducing the friction when something slides on thesurface of the artificial turf surface 1002. The elongated granules 1002and/or irregularly shaped granulate 1002 may be made of severaldifferent materials. In one example the elongated granules 1002 and/orirregularly shaped granulate 1002 may for example be manufactured froman elastomeric compound or other flexible material.

The following examples are several possible practical examples ofartificial turf surfaces that use the irregularly shaped grains asartificial turf infill. Artificial turf infill made from irregularlyshaped grains is referred to as “polymer agglomerate.” All weights referto the amount of material distributed on the surface of an artificialturf carpet. The polymer agglomerate is placed on top of the sand layer.The term e-layer refers to a substructure made of a shock absorptivelayer of rubber granulate, matting, or other material under theartificial turf carpet.

-   Example 1 (artificial turf carpet with a 40 mm high pile):    -   Polymer agglomerate: 5 kg/m²    -   Sand: 15 kg/m²    -   e-layer: 25 mm-   Example 2 (artificial turf carpet with a 40 mm high pile):    -   Polymer agglomerate: 7.5 kg/m²    -   Sand: 12.5 kg/m²    -   e-layer: 25 mm-   Example 3 (artificial turf carpet with a 40 mm high pile):    -   Polymer agglomerate: 5 kg/m²    -   Sand: 15 kg/m²    -   e-layer: 30 mm-   Example 4 (artificial turf carpet with a 40 mm high pile):    -   Polymer agglomerate: 5 kg/m²    -   Size distribution: 0-2.5 mm (sorted by sieve size)    -   Sand: 15 kg/m²    -   e-layer: 25 mm-   Example 5 (artificial turf carpet with a 40 mm or 60 mm high pile):    -   Polymer agglomerate: 5 kg/m²    -   Size distribution: 2.5-12.5 mm (sorted by sieve size)    -   Sand: 15 kg/m²    -   e-layer: 25 mm

In the 5 above examples, the numerical values may be varied by up to10%, 20, or 30% to produce alternative examples.

In examples 1 through 3, so size distribution of the polymer agglomerateis given. It is understood that any sieve size between 1 and 12.5 mm maybe used to sort agglomerate for these two examples.

In examples 4 and 5: Grains that pass through the 2.5 mm sieve are usedfor example 4. The grains that are caught by the 2.5 mm sieve, but passthrough a 12.5 mm sieve are used for example 5.

LIST OF REFERENCE NUMERALS

-   -   100 artificial turf surface    -   102 artificial turf carpet    -   104 pile    -   106 backing    -   108 artificial grass fibers    -   110 tufting    -   112 base layer    -   114 infill    -   116 irregularly shaped grains    -   118 void    -   200 artificial turf surface    -   202 sand    -   302 fibrous extensions    -   304 branched structure    -   306 hook like structure    -   400 agglomerator    -   402 hopper    -   404 waste thermoplastic    -   408 agglomerator disk    -   500 extruder    -   502 orifice    -   502′ orifice    -   504 extrusion die plate    -   506 cutting system    -   600 first portion    -   602 opposing portion    -   700 provide an artificial turf carpet with a pile,    -   702 form an agglomerate comprising least one type of        non-elastomeric thermoplastic into irregularly shaped grains to        provide an infill for the artificial turf carpet    -   800 artificial turf surface    -   801 top infill layer    -   802 regularly shaped granules    -   1000 artificial turf surface    -   1002 elongated granules or irregularly shaped granulate

1. An artificial turf surface comprising: an artificial turf carpet witha pile, wherein the artificial turf carpet comprises a backing; whereinthe artificial turf carpet further comprises artificial grass fibers,wherein the artificial grass fibers are tufted into the backing, whereinthe artificial grass fibers form the pile, wherein the artificial grassfibers are secured to the backing; and artificial turf infilldistributed within the pile, wherein the artificial turf infillcomprises irregularly shaped grains, wherein the irregularly shapedgrains comprise an agglomerate, wherein the agglomerate comprises atleast one type of non-elastomeric thermoplastic, wherein at least aportion of the grains have fibrous extensions.
 2. The artificial turfsurface of claim 1, wherein at least 50%, at least 60%, at least 70%, atleast 80%, at least 90%, or at least 95% of the irregularly shapedgrains have a curved profile.
 3. The artificial turf surface of claim 1,wherien at least 40%, 50%, 60%, 70%, 80%, or 90% of the grains have thefibrous extensions.
 4. The artificial turf surface of claim 1, whereinin at least 50%, 70%, or 90% of the portion of the grains the fibrousextensions comprise at least 30% of the weight of the grains.
 5. Theartificial turf surface of claim 1, wherein the at least one types ofnon-elastomeric thermoplastic comprise recycled artificial turf fibers.6. The artificial turf surface of claim 1, wherein the irregularlyshaped grains have a longitudinally stretched out and curved volumeexpansion with ratios of length to diameter/cross-section within 1:2 to1:50.
 7. The artificial turf surface of claim 1, wherein the irregularlyshaped grains have a longitudinally stretched out and curved volumeexpansion with ratios of length to diameter/cross-section within any oneof the following: 1:4 to 1:50, 1:8 to 1:50, 1:16 to 1:50, and 1:32 to1:50.
 8. The artificial turf surface of claim 1, wherein the irregularlyshaped grains have a sieve size between 0.2 mm and 12 mm.
 9. Theartificial turf surface of claim 1, wherein irregularly shaped grainshave a thickness between 0.05 mm and 2 mm.
 10. The artificial turfsurface of claim 1, wherein the at least one type of non-elastomericthermoplastic comprise any one of the following: a least onethermoplastic polymer, a polyolefm, waste plastic, fibrous wasteplastic, pre-consumer yarn, post-consumer yarn recovered syntheticsports fields, artificial turf fiber, recovered waste plastic, polyethylene, polypropylene, a polyethylene and polypropylene mixture,LLDPE, HDPE, LDPE, MDPE, PP, PE, a polyolefin, and combinations thereof.11. The artificial turf surface of claim 1, wherein the at least onetype of non-elastomeric thermoplastic comprise any one of the following:recycled packaging material, poly ethylene food packaging, polyethylenefood packaging, and combinations thereof.
 12. The artificial turfsurface of claim 1, wherein the fibrous extensions of the irregularlyshaped grains interlock with any one of the following: the artificialgrass fibers, the fibrous extensions of other irregularly shaped grains,and combinations thereof.
 13. The artificial turf surface of claim 1,wherein at least a portion of the fibrous extensions are branched and/orhook shaped.
 14. The artificial turf surface of claim 1, wherein theartificial turf surface further comprises a sand layer between thebacking and the artificial turf infill.
 15. The artificial turf surfaceof claim 1, wherein the artificial turf surface further comprises a topinfill layer, wherein the irregularly shaped grains are between thebacking and the top infill layer.
 16. The artificial turf surface ofclaim 15, wherein the top infill layer comprises regularly shapedgranules.
 17. The artificial turf surface of claim 16, wherein theregularly shaped granules comprise any one of the following: a least onethermoplastic polymer, a polyolefin, waste plastic, fibrous wasteplastic, pre-consumer yarn, post-consumer yarn recovered syntheticsports fields, artificial turf fiber, recovered waste plastic, recycledpackaging material, polyethylene food packaging, poly ethylene,polypropylene, a polyethylene and polypropylene mixture, LLDPE, HDPE,LDPE, MDPE, PP, PE, and a polyolefin, and combinations thereof.
 18. Theartificial turf surface of claim 16, wherein the regularly shapedgranules comprise any one of the following: an elastomeric compound,rubber, crumb rubber, EPDM, and combinations thereof.
 19. The artificialturf surface of claim 16, wherein the regularly shaped granulescomprises at least 50%, 70%, 90%, or 95% of the top infill layer byweight.
 20. The artificial turf surface of claim 15, wherein the topinfill comprises elongated granules.
 21. The artificial turf surface ofclaim 20, wherein the top infill comprises at least 40%, 50%, 60%, 70%,80%, 90%, or 95% of the elongated granules by weight.
 22. The artificialturf surface of claim 20, wherein the wherein the elongated granules areformed from any one of the following: an elastomeric compound, shavingsfrom at least one block of an elastomeric compound, rubber, crumbrubber, EPDM, and combinations thereof.
 23. The artificial turf surfaceof claim 1, wherein the artificial turf surface further comprises a sandlayer between the backing and the artificial turf infill, wherein theartificial turf surface further comprises a top infill layer, whereinthe irregularly shaped grains are between the backing and the top infilllayer, wherein the top infill comprises irregularly shaped granulate,wherein the irregularly shaped granulate comprises shavings from atleast one block of an elastomeric compound.
 24. The artificial turfsurface of claim 1, wherein the agglomerate at least comprises 80%, 90%,95%, or 99% by weight the at least one type of non-elastomericthermoplastic.
 25. A method of manufacturing an artificial turf system,wherein the method comprises: providing an artificial turf carpet with apile, wherein the artificial turf carpet comprises a backing; whereinthe artificial turf carpet further comprises artificial grass fibers,wherein the artificial grass fibers are tufted into the backing, whereinthe artificial grass fibers form the pile surface, wherein theartificial grass fibers are secured to the backing; and forming anagglomerate comprising at least one type of non-elastomeric plastic toform irregularly shaped grains to provide an infill for the artificialturf carpet.
 26. The method of claim 25, wherein at least 50%, at least60%, at least 70%, at least 80%, at least 90%, or at least 95% of theirregularly shaped grains have a curved profile.
 27. The method of claim25, wherien at least 40%, 50%, 60%, 70%, 80%, or 90% of the grains havethe fibrous extensions.
 28. The method of claim 25, wherein in at least50%, 70%, or 90% of the portion of the grains the fibrous extensionscomprise at least 30% of the weight of the grains.
 29. The method ofclaim 25, wherein the agglomeration of the at least one type ofnon-elastomeric thermoplastic into the agglomerate and the forming ofthe irregularly shaped grains from the agglomerate is performed using anagglomerator.
 30. The method of claim 29, wherein the agglomerator is afriction agglomerator.
 31. The method of claim 25, wherein forming ofthe irregularly shaped grains is performed using an extruder.
 32. Themethod of claim 30, wherein the extruder comprises any one of thefollowing: an underwater pelletizing system, a watering pelletizingsystem, a strand pelletizing system, and hot-cut pelletizing system. 33.The method of claim 31, wherein the extruder comprises an extrusion dieplate, wherein any one of the following: the extrusion die plate has atleast one orifice for extruding the agglomerate, wherein the at leastone orifice has a first portion and an opposing portion, wherein thefirst portion is rough, wherein the opposing portion is smooth to formirregularly shaped grains that have a curved profile; the extruder dieplate comprises multiple orifices, and the multiple orifices have atleast two distinct sizes and/or the orifices are irregularly shaped; andcombinations thereof.
 34. The method of claim 31, wherein the extrudercomprise a cutting system for cutting the irregularly shaped grains,wherein the cutting system is configured for producing irregularlyshaped grains with varying lengths.
 35. The method of claim 25, whereinthe method further comprises mixing at least one additive into theagglomerate before forming the irregularly shaped grains.
 36. The methodof claim 35, wherein the at least one additive comprises any one of thefollowing: a dye, a colorant, a UV-stabilizer, a flame retardant, abinding agent, a blowing agent, an anti-seize agent, a lubricant, afiller, a compatibilizer, and combinations thereof.
 37. The method ofclaim 25, wherein the method further comprises recycling used artificialturf to provide the at least one type of non-elastomeric thermoplastic.38. A method of manufacturing an artificial turf surface, wherein themethod comprises the method of claim 25, wherein the method furthercomprises: installing the artificial turf carpet; and distributing theirregularly shaped grains within the pile to form an artificial turfsurface.
 39. The use of an agglomerate as infill for artificial turf,wherein the agglomerate comprises irregularly shaped grains formed fromat least one type of non-elastomeric thermoplastic, and wherein at leasta portion of the grains have fibrous extensions.
 40. The use of anagglomerate as infill for artificial turf of claim 38, wherein at least50%, at least 60%, at least 70%, at least 80%, at least 90%, or at least95% of the irregularly shaped grains have a curved profile.